Human Neuropeptide S (NPS) is a 20 residue peptide showing the primary sequence: SFRNGVGTGMKKTSFQRAKS (SEQ ID NO: 1). This sequence is also well conserved among species; in particular, the serine (S)N-terminal residue of NPS is conserved among all species examined so far. After its pairing with NPS, the previously orphan G-protein coupled receptor (GPCR) GPR154 was named the NPS receptor and abbreviated as NPSR.
NPS peptide transcript is expressed predominantly in a small group of neurons located between the locus ceruleus (LC), the Barrington nucleus, and the parabrachial nuclei. NPSR mRNA is expressed throughout the central nervous system with the highest concentration in olfactory structures, the amygdaloid complex, the paraventricular thalamic nucleus, the subiculum, and the lateral (LH), dorsomedial (DMH), and ventromedial hypothalamus (VMH). NPSR shows potential for involvement in several biological processes such as arousal, anxiety, and food intake.